When Marcel Duchamp drew a moustache on a reproduction of arguably the most famous painting, and indeed face, in the world - the Mona Lisa - he articulated a universal human compulsion to make a mark, and for that mark to make a statement. A baby uses its finger to draw a line through good, a teenager scrawls a 'tag' on a brick wall, a young adult perfects a unique signature to access the world of personal finance. Each act of mark-making is a form of drawing and for this reason drawing is the most accessible and versatile of mediums. Nearly all artists draw, whether as a research tool, a private mode of expression, or as a public statement. In addition, all artists have their own personal 'drawing book' of images that hold significance and inspiration for their practice.

It would be useful to take a brief look at how the boundaries of drawing and indeed all artistic practice have been challenged in the post war era. Drawing was somewhat out of vogue among the avant-garde in the 1940s as it was seen as a skill that needed to be scquired. The Abstract Expressionists believed that it was unnecessary to draw and yet managed to incorporate characteristics of drawing into their paintings, and thereby put it on an equal footing with painting. In the late 1940s and 50s, figuration was left behind and the line was used as evidence of raw emotional expression. In these paintings the scale of drawing is blown up and line operates between description and non-description. In 1953, Robert Rauschenberg requested a drawing from Abstract Expressionist painter Willem De Kooning and erased it, framing the blank sheet of paper as his own work of art. It is significant that he opened up the arena for art activity by deliberately erasing a drawing - the symbol of artistic authenticity - declaring that a work of art could be an act of negation, and the direct hand of the artist was no longer necessary.

During the 1960s, artists like Agnes Martin and Sol LeWitt celebrated the purity and simplicity of drawing in the name of abstraction. At the same time, drawing's obvious link with technology and industrialisation was exploited by Pop artists like Andy Warhol and Roy Lichtenstein to serve the needs of representation. As the object dematerialised throughout the late 1960s and early 70s, drawing became a way of recording an action or intellectual statement. It became the medium of choice, alongside writing, for expressing art as an idea, and has remained at the core of this enduring strand of contemporary practice. At the same time it was released from the page, as artists declared that art could be a performance, a temporally-constrained event. Drawing became a line made by walking in a field or cutting through a house. In the 1980s, painting and sculpture became more dominant as artists returned to object-based practice. By the 1990s, an artist working with video or sculpture was not necessarily directly involved in producing their work, as new technologies in fabrication and new media were employed. Yet during this decade certain artists began to champion drawing, attracted once again by the direct creative experience it offered.

Yet why should drawing be isolated and discussed separately? There is a sense of 'rescuing' the medium in order to re-evaluate its status. Drawing is simultaneously fundamental and peripheral, central and subsidary. In its more traditional role as preparatory sketch it has had a steady poorer cousin of painting. The recent interest in drawing was partially revived by artist-curated exhibitions such as Deanna Petherbridge's The Primacy of Drawing, 1991, Michael Craig-Martin's The Stage of Drawing: Gesture and Act, 2003. All three acknowledged the importance of drawings of the past and present to the development of contemporary art practice. Struck by the 'modernity' of drawings of the past, Craig Martin has suggested:

"...that this is because qualities we have come to value most highly in art in the twentieth century have always been present in art, but usually in the past have characterized only modest and 'secondary work'; that is, drawings. These characteristics include spontaneity, creative personal vision, technical diversity, modesty of means, rawness, fragmentation, discontinuity, unfinishedness, and open-endedness. These have always been the characteristics of drawing."

This re-evaluation of the special attributes of drawing and their application to all manner of working methods is key to the changing and elevated status of the medium. Artists have always highly valued drawings and sketches; as Erika Naginski has noted, Leonardo da Vinci understood drawing to be "part of a process which is constantly going on in the artist's mind; instead of fixing the flow of imagination it keeps it in flux". On the other hand, the influential American Modernist art critic Clement Greenberg failed to recognize the value of da Vinci's drawings, which he saw as "sheer rumination, reverie, wish-fulfillment, thinking [that] amounts to works of art only in the never saw existence." Artists have worked hard to reassert that special quality of drawing, described by Stephen Farthing as follows: "the best drawings create a sense of limbo, a conceptual space where ideas can be stored in an untraceable state... the information just sits there, it doesn't go away." In her text for the book What is Drawing?, Naginski suggests that it is this dimension of drawing that has been incorporated into the practice of particular contemporary artists - "drawing as an activity that exemplifies an imagination in flux".

The Museum of Modern Art in New York has mounted a series of exhibitions themed around drawing, including Drawing Now, 1976, Allegories of Modernism: Contemporary Drawing, 1992, and Drawing Now: Eight Propositions, 2003, a unique attempt to track the development od drawing practice over the past 40 years. The first of these exhibitions was mounted at the height of Minimalism, a movement that brought together the logical, diagrammic aspects of drawing and the concerns of three-dimensional objects, as well as Conceptualism, which promoted the aforementioned dematerialization of the art object. The expansion of the field of sculpture, in particular, was seen as key to the re-alignment of drawing. Richard Serra was one of the main practitioners in this expanded field, articulating the importance of drawing for his generation, finding process to be everything. "Anything you can project as expressive in terms of drawing - ideas, metaphors, emotions, language structures - results from the act of doing", which is to say, as Serra famously went on to declare, "Drawing is a verb."

The Museum of Modern Art's exhibition of 2003, Drawing Now: Eight Propositions, turns full circle and in its selection showcases the work of artists whose drawing practice is related to that of their nineteenth century predecessors, who favored the polished, finished article over the working document. Yve-Alain Bois has described this as "projective" drawing; that is, it depicts something that has been imagined before it is drawn. This shift heralds above all a new attitude towards drawing by contemporary artists; the status of drawing is no longer under question. As Laura Hoptman points out in the catalog accompanying Drawing Now, "With all respect to Serra, for many artists today drawing is not a verb but a noun."

Today, what constitutes drawing is being revisited as artists exploit the infinite potential of the discipline. We find artists who draw on vases, on globes, on found materials, or who 'draw' using the entire three-dimensional space of the gallery. In contrast to the predominantly detached stance of the 1990s, contemporary drawing celebrates the artist's touch, as the process of 'crafting' an object is once again valorized. Labor intensive processes, carried out by the artists themselves (with assistance in some cases), are an important an integral component of the work of the artists discussed here. This interest in craftsmanship seems to have a moral and ethical dimension and could be perceived as a reaction against modernist and Postmodernist attempts to undermine these aspects of art making. It is now possible to adopt a personal subjective stance, especially as this is not perceived to be mutually exclusive with a conceptual approach.

Artists do not work in a vacuum, and the market as a role to play in any art trend or shift in focus. With the prosperity of the 1960s, art became a lucrative commodity and commercial galleries opened new spaces in more affluent areas to exhibit maquettes and drawings of large scale works. The deliberate rejection of the consumable object inherent in environmental, conceptual and minimal art was in part a reaction to these new economic interests. In Britain, a wave of small and experimental commercial galleries is once again promoting drawing as a way of supporting the new enthusiasm amongst emerging artists. Drawing is particularly accessible and affordable to collectors, offering them at the same time the element of the hand made, the exquisiteness of touch, and a sense of intimacy. The 'personality' of a drawing reflects the personal taste and interests of an individual collector. Unlike works in print, video, or film, that require documentation to authenticate the work, the uniqueness of a drawing provides evidence of the artist's hand and the artist's signature as validation of its originality. Encouraged by the commercial success of artists who predominantly draw, many younger artists continue drawing once they have left college or incorporate it into a multi-disciplinary practice.

The support structures for art practice are also reassessing their treatment of drawing. In Britain, there are now a number of established graduate courses that focus solely on drawing, and drawing fellowships attached to academic institutions. New forums for celebrating contemporary drawing have been initiated, such as the International Biennial of Drawing in Pilsen in the Czech Republic, which began life in 1996 as a local event then expanded to take in Central European countries, and in 2004 took on an international remit; or the Montreal Biennial which has focused on drawing in recent years.

Institutions have always collected drawing - the importance of the medium in the 1970s led to the establishment, by The Museum of Modern Art in New York, of a separate Department of Drawings in 1971. Up until that point, drawings were collected to enhance viewer's understanding of the Museum's primary collections of painting and sculpture. In the context of a museum, drawing, more than any other medium, calls into question whether the primary function of the institution is to conserve a work of art for longevity, or make it available for public display. As works on paper fade as a consequence of exposure to light, they have often been shown separately to paintings or sculptures, so that light levels can be kept low. This has resulted in a sense that drawing is a subsidiary discipline, suitable only for the secretive plan chest or the chapel-like, dimly lit gallery. This debate has still to be resolved, as new conservation techniques are researched, and as institutions are continually challenged to accommodate the evolving practice of artists.